Resettable circuit interrupter



June 21, 1938. M. GUETT 2,121,691

RESETTABLE cmcuxr INTERRUPTER Filed July 10, 1955 1 a as 4 INSULATION 2 4a 48 2g INSULATION INSULATION rm I INVENTOR MONROE GUETT BY HIS ATTORN Patented June 21, 1938.

UNITED STATES RESETTABLE CIRCUIT INTERRUPTER Monroe Guett, Hartford, Conn, assignor to The Arrow-Hart & Hegeman Electric Company, Hartford, Conn, a corporation of Connecticut Application July 10, 1935, Serial No. 30,722

14 Claims.

This invention relates to devices for manually opening and closing an electric circuit and for automatically opening the circuit upon the occurrence of a predetermined overload current. More particularly this invention relates to devices of the above type which are adaptable for use with tools and small electrical apparatus in which it is only desired to have the circuit closed for a short period of time. However, the principles of this invention may be applied to devices for controlling larger electrical apparatus and devices in which the circuit may be closed over longer periods;

It isan object of my invention to provide a manually and automatically operable circuit interrupter of simplified construction and low cost of manufacture.

Another object of my invention is to provide an improved manually and automatically operable circuit interrupter in which the circuit may not be maintained closed by holding the handle in closed circuit position "during the continuance of an overload.

Another object of my invention is to provide a manually and automatically operable circuit interrupter in which the manually operable means will automatically open the circuit upon removal of pressure from the actuating handle and will at the same time reset the automatic mechanism in case the circuit has been opened by reason of the action of an overload current.

Another object of.my invention is to make a circuit breaker of the above type in which the parts may be housed within a small space without interfering with the positive and accurate operation of the device.

Other objects and advantages'of my invention will appear as it is described in connection with the accompanying'drawing.

In the drawing:'

Figure 1 is a plan view of the'interior of a I manually and automatically operable circuit interrupter embodying the principlesof my invention. In this view. the parts are in the position I taken when the circuit is manually opened.

Figure 2 is a view of my invention similar to I Figure 1 but with the parts in closed circuit po- 7 sition.

section taken on vention.

Figure 4 is a left end section view with the section taken along line 4- 4 of Figure 1.

Figure 5 is a plan view of my inventionsimi-.-

lar to Figure l, but with the parts inthe position.

mechanism is mounted upon the base ll! .of a two part hollow insulating casing, the cover l2 of which is removed in Figures 1, 2 and 5, to clearly show the circuit interrupter mechanism. As illustrated the casing is rectangular in shape, but obviously it may take other suitable forms. The current enters the switch through a wire terminal, denoted generally in Figure 1 by the numeral l4, which is stamped in L shape from sheet metal and has one arm Ila secured to the floor of the base ill by rivets or other suitable means. The other arm 14b of this terminal l4 extends up at right angles to the floor of the baseadjacent the left hand wall and has a threaded aperture provided in its end for the reception of a binding screw l6 by means of which a wire may be secured to the terminal. The arm Mb near its bottom is enlarged by a lateral extension to and has .mounted upon this enlargement a contact button l8 with which cooperates a similar contact button 20 which is mounted upon the end of a resilient arm 22a. of a movable contact, denoted generally in Figure 1 by the numeral 22. This movable contact 22 has another arm 22b extending substantially at right angles to the arm 22a upon the end of which is mounted a contact button 24 which is adapted to cooperate with a similar contact button 26 hereinafter more particularly described. The movable contact 22 is secured to the floor of the base Ill by a lug extending laterally from the arm 22a adjacent the, juncture of the arms 22a. and 22b. Thus mg 220 is bent at right angles to# the plane of the arm 22a. so as to lie flat upon the floor of the base I!) while the arms 22a and 22b lie in planes perpendicular to the floor of-the casing part l0. y l

The engagement of contact buttons 18 and 20 scribed and by means of these contacts, the normal control of the circuit is effected. The engagement of thecontact buttons .24 and 26 is controlled automatically by current responsive mechanism hereinafter described, so that these contacts form means for interrupting the circuit upon the occurrence of overload or abnormal conditions. I

The contact button 26 is mounted upon an is controlled manually as will hereinafter be del arm 28aextending from the central portion of a conducting post, denoted generally by the nu-' meral 23 in Figure 1. This post has one end turned out at right angles to it forming a foot 23b which lies upon the floor of the casing part I3 and is secured thereto by rivets whereby the post is secured in position. The top of the post has an arm 23c extending at right angles thereto for mounting one leg 33 of a current-responsive latch, denoted generally by numeral 33 in Figures 1 and 2. This leg 33 is made of bimetal so as to bend upon the passage therethrough of an overload current. The arm 23c has a finger 23d extending from the end of it, which finger passes through an aperture in the enlarged end portion of the bimetallic leg 33. Metal washers 3| and 32 may be provided on each side of said enlarged end of the bimetallic leg 33 so that as the end of the finger 23d is peened over, said enlarged end of the bimetallic leg will be mounted ilrmly upon the post 23. The other end of the bimetallic leg 33 is riveted to one end of the cross portion of an inverted T-shaped member denoted generally in Figure 3 by the numeral 34 while the other end of the cross portion of this T member-has riveted to it a bimetallic leg 33 similar to the leg 33 and parallel to said leg 33. This bimetallic leg 33 has its other end secured to the end of one arm 33a of a wire terminal member denoted generally in Figure 1 by the numetal 33. This arm 33a lies along the same wall of the casing part l3 adjacent which the post 23 is mounted and this arm 33a is bent at right angles to the main body of the wire terminal 33. The bimetallic leg 33 is mounted upon this arm 33 in the same fashion as the bimetallic arm 33 is mounted upon the post 23. The main body of the wire terminal 33 lies along the wall of the casing opposite to the wire terminal I 4 and has an enlargement with a screw-threaded aperture in which is binding screw 43 by means of which a feed wire may be secured to the terminal. The wire terminal 33 is secured to the floor of the base l3 by screws or any other suitable means passing through a lug 33b bent at right angles to the main body of the terminal.

Referring back to the T member 34 it will be noted that the leg portion 34c extends toward the wall of the casing farthest from the contacts 24 and 23 and is adapted to be engaged by the nose :tlIa of a pgotlfd member 33 whose function and ruc ure ereinafter m scribed ore particularly de The means for causing the manual engagement of the contacts l3 and 23 will now be described. The movable contact arm 22:: is normally biased to open circuit position (see Figure-1) by the inherent resilience of this arm. In order to move the contact 23 into engagement with the contact ii an L shaped operating lever denoted generally in Figure 5 by numeral 42, is pivotally mounted upon a pin 44 located in the corner of the base diagonally opposite the corner in which are the contacts 24, 23. This pin 44 extends up from zhgtflolor oftlthe base l3, and passes through the e ra por on of one arm 42a of the lever. This arm 42a lies operating the other arm 42b extends outside the casing for engagement by the hand of the operator:' Upon the end of the inner arm 42a are mounted a pair of circular insulating washers 43, one on each side of the arm 4211. These washers are secured in place by a pin 41 passing through them and through the end of the arm 42a and this pin 41 has an extension directed away from the floor of the casing part i 3 against which extension presses within the casing but an and 48a of a wire spring 43 which is coiled about an extension of the pivot pin 44 and tends to bias the operating lever to open-circuit position as shown in Figure 1 by reason of the other end 43b of the spring engaging with an extension of the pivot pin 33 upon which the hereinbefore mentioned member 33 is mounted. The arm 42a is of such length that the insulating washers 43 will engage with the arm 22a of the movable contact when the operating lever 42 is depressed, as shown in Figures 2 and 5, to cause the movable contact button 23 to engage with the fixed contact button i8.

The mechanism for automatically opening the circuit upon the occurrence of an overload current passing through the device will now be described. This mechanism comprises a pair of links denoted generally in Figure 1 by numerals 33 and 32. 'I'he link or member 33 hereinbefore mentioned is pivoted upon the hereinbefore mentioned pin 53 and may be a sheet metal stamping having a nose 33a engaging with the end of the latch member 33, as shown in Figure 2, when the parts are in closed circuit position. This member 33 is biased in a clockwise direction by a spring denoted generally in Figs. 2 and 3 by numerals 34, which is wound around the extension of the pivot. pin 33 and has one end 34a pressing against the wall of the casing beneath the oper-,- ating lever 42 and its other end pressing against a lug 33b bent up at right angles to the plane of the member 33. The member 33 is pivotally connected by a pin 33 to one end of the link 32. This link 32 comprises a pair of sheet metal stampings each having one end ofl'set from the other (see Figure 4) by means of a double right angle bend formed in the center of the stampings. One stamping is placed on one side and one on the other side of the member 33 at the. pivot pin 33 with the ofl'set ends of stampings spaced apart from each other, as illustrated in Figure 4, so as to straddle the movable contact arm 22b. The link 32 is connected with the movable contact arm 22b by an insulating connection comprising an inverted T-shaped member 13 formed from sheet insulating whose leg 13a extends up from the lower side of the contact arm 22b through an aperture in the central portion of said arm and also through an aperture in a small insulating plate 12 placed upon the other side of the contact arm 22b. The arm 13a of this insulating member 13 is provided with an aperture for the reception of a shaft or pin 14 passing transversely through the end portions of the two stampings comprising the link 32.

The contact arm 22b may be biased to open circuit position in which case it will assist the bias of the spring 34 when the automatic mechanism is operated upon-the occurrence of overload. Or the contact arm 22b may be biased to closed circuit position in which case the spring 34 will have to be stronger than the bias of the contact arm 22b in order to overcome this bias in causing separation of the contact buttons 24 and 23 when the overload mechanism operates.

From the foregoing it will be observed that when the handle or operating lever 42 is moved to closed-circuit position as illustrated in Figure 2 to cause engagement of the contacts l3 and 23 the automatic releasing mechanism is held from operating the contact arm 22b to cause separation of the overload contacts 24 and 23 solely by reason of the engagement of the nose 33a on the member 33 with the end of the current-responsive latch member 33. If, while the parts are held by manual pressure in the position shown in Figure 2, an overload should occur the heat gen- -erated in the bimetallic members 30 and- 38 will cause clockwise warping and disengagement of the latch member 33 from the nose 60a whereby the operation of the spring 64 is given effect to cause rotation of the member 60 in a clockwise direction and movement of the link 62 to pull the contact arm 22b and contact 24 away from the fixed circuit breaker contact 26 whereby the circuit is automatically interrupted irresp ctive of whether or not-the manually controlled con- I tacts l8 and 20 are held in engagement.

It should be observed that upon release of the handle or operating lever 42, the spring 48 will move the handle to the position shown in Figure 1 and in case the circuit has been automatically interrupted and the parts are in the position shown in Figure 5, will cause the insulating washers 46 to engage with the knee of the linkage connection 6!], 62 tending to align the links 60 and 62 and hence move the link 60 in a counter-clockwise direction to again engage the nose 60a with the end of the latch member 33. Thus the device autoniatically resets itself upon the release of the handle to open-circuit position. The operating lever 42 is a free member having no permanent connection with either the overload mechanism or the contact arm 22a, but, it causes operation of those parts merely by abutment against them.

From the foregoing it will be apparent that I have devised a. circuit interrupter of a small number of parts which may be inexpensively manufactured and which will be accurate and positive in operation. It will also be noted that the circuit may not be held closed by continued pressure upon the operating handle while the overload persists in the circuit.

Many modifications within the scope of my invention will occur to those skilled in the art, therefore I do not limit myself to the specific form of the embodiment disclosed.

I claim: j

1. In a circuit interrupter, fixed and movable manually controlled contact members, fixed and movable automatically controlled contact members operable independently of the manually controlled contact members, mechanism for engaging and disengaging said automatically operable members comprising a plurality of pivotally,

connected links one of which is connected to said movable automatically operable contact member, means operated by the occurrence of an overload in the circuit .to release said link mechanism, and a hand lever for moving said manually controlled contact members into engagement, said lever engaging directly with said manually movable contact member upon operation in one direction and directly with said link mechanism upon movement in the other direction, whereby said link mechanism may be reset.

2. In a circuit interrupter, fixed contact members, resiliently mounted movable contact members engageable with difierent fixed contact members, one of said movable contact members being manually controlled, the other of said movable contact members being automatically controlled, a hand lever, mechanism automatically operable upon occurrence of an overload current to cause said automatically controlled contact member todisengage its fixed contact member, said mechanism including a plurality of pivotally connected links one of which is pivotally connected to said automatically controlled movable contact member and another being mounted on a fixed pivot, said lever engaging with said manually movable contact member upon movement in one direction and with said automatic mechanism upon movement in the other direction whereby to reset said automatic mechanism.

3. In a circuit interrupter, fixed contact members, resiliently mounted movable contact members engageable with different fixed contact members, one of said movable contact members being manually controlled, the other of said movable contact members being automatically controlled, a hand lever having a pivotal mounting independent of said movable contact members, mechanism automatically operable upon the occurrence of an overload current to cause said automatically controlled contact member to disengage its fixed contact member, said mechanism including a plurality of pivotally connected links one of which is pivotally connected to said automatically controlled movable contact member and another being mounted on a fixed pivot, said lever engaging with said manually movable contact member upon movement in one direction and with said automatic mechanism upon movement in the other direction whereby to reset said automatic mechanism, and means biasing said manually movable contact member out of engagement with its fixed contact member.

4. In a circuit interrupter, fixed contact mem-- bers, resiliently mounted movable contact members engageable with different fixed contact members, one of said 'movable contacts being manually controlled, the other of said movable contact members being automatically controlled, a hand lever having a pivotal mounting independent of said movable contact members, mechanism automatically operable upon the occurrence of an overload current to cause said automatically controlled contact member to disengage its fixed contact member, said mechanism including a plurality of pivotally connected links one of which is pivotally connected to said automatically controlled movable contact member and another being mounted on a fixed'pivot, said lever engaging with said manually movable contact member upon movement in one direction but being disconnected from said manually movable contact member whereby upon movement in the other direction said lever may engage with said automatic mechanism to reset it.

5. In a circuit interrupter. fixed contact members, resiliently mounted movable contact members engageable with difierent fixed contact members, one of said movable contact members being manually controlled, the other of said movable contact members being automatlcally controlled, a hand lever having a pivotal mounting independent of said movable contact members, mechanism automatically operable upon the currence of an overload current to cause said automatically controlled contact member to disengage its fixed contact member, said mechanism including a plurality of pivotally connected links the other direction said l'ever may engage with said automatic mechanism to reset it, and means biasing said manually movable contact membe out of engagement with its fixed contact member. 6. In a circuit interrupter, fixed contacts, a

v unitary contact member havingindependently movable portions engageable with different fixed contacts, means automatically operated by the occurrence of an overload current to cause disengagement of one of said movable portions from its fixed contact, a. hand lever movable in one direction to engage with the other movable por tion and to cause engagement of it with its fixed contact, said hand lever when moving in the opposite direction engaging said automatic mechanism to reset it.

7. In a circuit interrupter, fixed contacts, a unitary contact member having independently movable portions engageable with diiferent fixed contacts, means automatically operated by the occurrence of an overload current to cause disengagement of one of said movable portions from its fixed contact, a hand lever having a lostmotion connection with the other movable portion and causing it upon movement in one direction to engage with its fixed contact, said hand lever when moving in the opposite direction engaging said automatic mechanism to reset it.

8. In a circuit interrupter, fixed contacts, a unitary contact member having independently movable portions engageable with different fixed contacts, means automatically operated by the occurrence of an overload current to cause disengagement of one of said movable portions from its fixed contact, a hand lever having a lostmotion connection with the other movable portion and causing it upon movement in one direction to engage with its fixed contact, said hand lever when moving in the opposite direction engaging said automatic mechanism to reset it, and means biasing said manually movable portion out of engagement with its contact.

9. In a circuit interrupter, fixed contacts, movable contacts, a hand lever movable'to cause one of said movable contacts to engage a fixed contact, a link connected to a second movable contact, said second movable contact being engageable with a second fixed contact, a member pivotally connected to said link, means biasing said second movable contact out of engagement with said second fixed contact, thermally responsive means releasable by the action of an overload current and normally holding said second movable contact in engagement with said second fixed contact against the bias of said biasing means, said hand lever causing re-engagement of said holding means and said member upon the movement of said lever away from the first-mentioned movable member.

10. In a circuit interrupter, fixed contacts, movable contacts, a hand lever movable to cause one of said movable contacts to engage a fixed contact, a link connected to a second movable contact, said second movable contact being engageable with a second fixed contact, a member pivotally connected to said link, means biasing said second movable contact out of engagement with said second fixed contact, thermally responsive means releasable by the action of an overload current and normally holding said second movable contact in engagement with said second fixed contact against the bias of said biasing means, said hand lever causing re-engagement of said holding means and said member upon the movement of said lever away from the first mentioned movable member, and means biasing said hand lever into open-circuit position, said handlever-biasing means being of sufiicient strength to cause the re-engagement of said holding means and said member to be automatic when the hand lever is relieved of manual pressure.

11. In a circuit interrupter, fixed contacts, a unitary contact member having movable portions, contacts on said portions adapted to engage and disengage with different fixed contacts, a hand lever movable to cause one of said movable contacts to engage a fixed contact, a link connected to move a second movable Contact, said second movable contact being engageable with a second fixed contact, a member pivotally connected to said link, means biasing said second movable contact out of engagement with said second fixed contact, thermally responsive means releasable by the action of an overload current and normally holding said second movable contact in engagement with said second fixed contact against the bias of said biasing means, said hand lever causing re-engagement of said holding means and said member upon the movement of said lever away from the first mentioned movable member.

12. In a circuit interrupter, fixed contacts, a unitary contact member having movable portions, contacts on said portions adapted to engage and disengage with different fixed contacts, a hand lever movable to cause one of said movable contacts to engage a fixed contact, a link connected to move a second movable contact, said second movable contact being engageable with a second fixed contact, a member pivotally connected to said link, means biasing said second movable contact out of engagement with said second fixed contact, thermally responsive means releasable by the action of an overload current and normally holding said second movable contact in engagement with said second fixed contact against the bias of said biasing means, said hand lever causing re-engagement of said holding means and said member upon the movement of said lever away from the first mentioned movable member, and means biasing said hand lever into open-circuit position, said hand lever biasing means being of sufficient strength to cause the re-engagement of said holding means and said member to be automatic when the hand lever is relieved of manual pressure.

13. In a circuit interrupter, fixed contacts, movable contacts, a freely mounted hand lever having no permanent connection with said movable contacts, said hand lever being movable to cause one of said movable contacts to engage a fixed contact, a link connected to a second movable contact, said second movable contact be ing engageable with a second fixed contact, a member pivotally connected to said link, means biasing said second movable contact out of engagement with said second fixed contact, thermally responsive means releasable by the action of an overload current and normally holding said second movable contact in engagement with said second fixed contact against the bias oi said biasing means, said hand lever causing re-engagement of said holding means and said member upon the movement of said lever away from the first-mentioned movable member.

14. In a circuit interrupter, fixed contacts, movable contacts, a freely mounted hand lever having no permanent connection with said movable contacts, said hand lever being movable to.

cause one of said movable contacts to engage a fixed contact, a link connected to a second movable contact, saidsecond movable contact being engageable with a second fixed contact, a member pivotally connected to said link, means bias ing said second movable contact out of engageill) ment with said second fixed contact, thermally responsive means releasable by the action of an overload current and normally holding said second movable contact in engagement with said second fixed contact against the bias of said hiasing means, said hand lever causing re-engagement of said holding means and said. member upon the movement of said lever away from the first mentioned movable member, and means biasing said hand lever into open-circuit position, said hand-lever biasing means being of sumcient strength to cause the re-engagement of said holding means and said member to be automatic when the hand lever is relieved of manual pressure.

MONROE GUEI'I. 

